more set filters

tested all types:

test.yml
```
---
- hosts: localhost
  connection: local
  gather_facts: True
  vars:
    cluster_interface: 'eth0'
    list1: [1,2,3,4,5,6]
    list2: [5,6,7,8,9,10]
    list3: "{{list1 + list2}}"
  tasks:
     - debug: msg="{{list1|union(list2)}}"
     - debug: msg="{{list3|unique}}"
     - debug: msg="{{list1|intersect(list2)}}"
     - debug: msg="{{list1|difference(list2)}}"
     - debug: msg="{{list2|difference(list1)}}"
     - debug: msg="{{list1|symmetric_difference(list2)}}"
```

output:
```

PLAY [localhost] **************************************************************

GATHERING FACTS ***************************************************************
ok: [localhost]

TASK: [debug msg="set([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])"] **********************
ok: [localhost] => {
    "msg": "set([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])"
}

TASK: [debug msg="set([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])"] **********************
ok: [localhost] => {
    "msg": "set([1, 2, 3, 4, 5, 6, 7, 8, 9, 10])"
}

TASK: [debug msg="set([5, 6])"] ***********************************************
ok: [localhost] => {
    "msg": "set([5, 6])"
}

TASK: [debug msg="set([1, 2, 3, 4])"] *****************************************
ok: [localhost] => {
    "msg": "set([1, 2, 3, 4])"
}

TASK: [debug msg="set([7, 8, 9, 10])"] ****************************************
ok: [localhost] => {
    "msg": "set([7, 8, 9, 10])"
}

TASK: [debug msg="set([1, 2, 3, 4, 7, 8, 9, 10])"] ****************************
ok: [localhost] => {
    "msg": "set([1, 2, 3, 4, 7, 8, 9, 10])"
}

PLAY RECAP ********************************************************************

```